KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.

Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/scripts/nsdeps b/scripts/nsdeps
new file mode 100644
index 000000000..d4b5ebcc2
--- /dev/null
+++ b/scripts/nsdeps
@@ -0,0 +1,54 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Linux kernel symbol namespace import generator
+#
+# This script requires a minimum spatch version.
+SPATCH_REQ_VERSION="1.0.4"
+
+DIR="$(dirname $(readlink -f $0))/.."
+SPATCH="`which ${SPATCH:=spatch}`"
+if [ ! -x "$SPATCH" ]; then
+	echo 'spatch is part of the Coccinelle project and is available at https://coccinelle.gitlabpages.inria.fr/website'
+	exit 1
+fi
+
+SPATCH_VERSION=$($SPATCH --version | head -1 | awk '{print $3}')
+
+if ! { echo "$SPATCH_REQ_VERSION"; echo "$SPATCH_VERSION"; } | sort -CV ; then
+	echo "spatch needs to be version $SPATCH_REQ_VERSION or higher"
+	exit 1
+fi
+
+generate_deps_for_ns() {
+	$SPATCH --very-quiet --in-place --sp-file \
+		$srctree/scripts/coccinelle/misc/add_namespace.cocci -D nsdeps -D ns=\"$1\" $2
+}
+
+generate_deps() {
+	local mod=${1%.ko:}
+	shift
+	local namespaces="$*"
+	local mod_source_files=$(sed "s|^\(.*\)\.o$|${srcroot}/\1.c|" $mod.mod)
+
+	for ns in $namespaces; do
+		echo "Adding namespace $ns to module $mod.ko."
+		generate_deps_for_ns $ns "$mod_source_files"
+		# sort the imports
+		for source_file in $mod_source_files; do
+			sed '/MODULE_IMPORT_NS/Q' $source_file > ${source_file}.tmp
+			offset=$(wc -l ${source_file}.tmp | awk '{print $1;}')
+			cat $source_file | grep MODULE_IMPORT_NS | LC_ALL=C sort -u >> ${source_file}.tmp
+			tail -n +$((offset +1)) ${source_file} | grep -v MODULE_IMPORT_NS >> ${source_file}.tmp
+			if ! diff -q ${source_file} ${source_file}.tmp; then
+				mv ${source_file}.tmp ${source_file}
+			else
+				rm ${source_file}.tmp
+			fi
+		done
+	done
+}
+
+while read line
+do
+	generate_deps $line
+done < modules.nsdeps